Background

Recently, astronauts returning from long-duration spaceflight have been found to have a syndrome of swelling of the optic nerve, impaired vision, and elevated spinal fluid pressure (also known as intracranial pressure [ICP]), which is similar to the syndrome of idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri. In astronauts, this syndrome is called visual impairment/intracranial pressure (VIIP). It is not possible to perform a spinal tap on astronauts in space to measure spinal fluid pressure. Noninvasive methods of estimating ICP exist but have not been tested compared to ICP methods in patients who are physiologically similar to astronauts.

Objective

The primary objective of this study is to determine the accuracy of two noninvasive methods of ICP measurement in comparison to standard, invasive ICP measurement. The two methods to be tested are:

Brief Protocol Summary

Adults with hydrocephalus or pseudotumor cerebri who have been recommended on the basis of standard clinical criteria to have ICP monitoring either by insertion of a temporary spinal catheter or by insertion of a needle into an existing shunt reservoir are eligible for this study.

The two noninvasive methods are based on the responses of the inner ear and middle ear to changes in ICP. The first method, TMD, measures tiny movements of the ear drum, and the second, DPOAE, is routinely used for newborn hearing screening.

After insertion of the spinal catheter or the needle in the shunt, subjects will undergo testing with the TMD and DPOAE in the lying, sitting, standing, and head-down tilt (10 degrees) position. In addition, testing will be performed during sleep, when normal fluctuations of ICP occur.

Eligibility

You may qualify to participate if:

You are an adult man or woman, 18–65 years of age

You have hydrocephalus or idiopathic intracranial hypertension (pseudotumor cerebri)

The purpose of this research study is to compare the accuracy of a noninvasive FDA-approved device, the ShuntCheck, and an investigational device that has not been approved by the FDA, the Micro-Pumper, to the standard Shunt Patency Study method for demonstrating shunt obstruction in patients 35 years and older who have had a shunt placed for adult hydrocephalus. Established patients with possible shunt obstruction may be eligible to participate.

Study Purpose: CRT ShuntCheck is a new test that is designed to find out if an indwelling shunt for patients with hydrocephalus or pseudotumor cerebri is working properly. It is the first device that measures shunt flow using a simple test on the skin, and it is not invasive. CRT ShuntCheck is intended to find out if the shunt is working, and the check can be done at the doctor’s office or at bedside, thereby making it much easier for the patient. It also does not require the patient to undergo extensive tests.

A sensor patch will be placed on the skin of the collar bone. The patch will cool the skin and will measure the change in skin temperature as the fluid flows through the shunt tubing. The patient will be asked to change position from sitting to lying down to standing and will be asked to walk and to move his/her arms and shoulders.

The purpose of this study is to determine if the sensor patch remains in good contact with the skin and records skin temperatures accurately when the patient moves.

Study Design: Exploratory

Study Sponsor: NeuroDx Development LLC

Subject Eligibility: Male or female 35 years and older and with indwelling shunt requiring evaluation. Must be able to comply with the study requirements.